German Patent Application No. DE 35 45 780 A1 describes a switching device. Depending on the position of the switchgear door, a blockable and releasable stop element generally prevents a tool from engaging in order to move the drawout circuit-breaker in the drawout frame when the switchgear door is open. The stop element is permanently connected to a guide rod, which can be blocked by a bolt in all positions--operating position, test position and disconnect position--allowing the bolt to be directly actuated via a flexible transfer element by opening the switchgear door. The sole purpose of this measure is personal protection.
U.S. Pat. Nos. 2,777,024, 2,921,998 and 4,044,113 describe switchgear with drawout circuit-breakers. U.S. Pat. No. 2,777,024 takes into account only the standard conditions which prevent the circuit-breaker from moving when activated or when the circuit-breaker is being turned on. There is no mention of a locking arrangement.
Unlike the present invention, in the arrangement described in U.S. Pat. No. 2,921,998, the locking arrangement is located on the circuit-breaker for safe replacement of the circuit-breaker.
As described in U.S. Pat. No. 4,044,113, a closure member interacts with the rails in order to access the actuating shaft of the traveling mechanism and blocks the drawout circuit-breaker in the test or disconnect position. At the same time, this prevents the circuit-breaker from being replaced.